Blood Flow Restriction Training After ACL Reconstruction: A Systematic Review of Early-Phase Strength, Morphology, Pain, and Neuromuscular Adaptations

ObjectiveThis systematic review aimed to evaluate the effects of blood flow restriction (BFR) training compared to traditional rehabilitation or high-load resistance training (HL-RT) on quadriceps strength, muscle morphology by cross-sectional area (CSA), pain and neuromuscular activation (NMA) following anterior cruciate ligament reconstruction (ACLR). MethodsA systematic review was performed according to PRISMA 2020 guidelines. Five databases (PubMed, Web of Science, MEDLINE Complete, CINAHL, and SPORTDiscus) were searched using the following equation : (blood flow restriction training OR blood flow restriction exercise OR blood flow restriction therapy OR BFR therapy OR KAATSU training OR occlusion resistance training) AND (anterior cruciate ligament injury OR ACL injury OR anterior cruciate ligament tear OR ACL tear OR ACL reconstruction). Only randomized controlled trials (RCTs) were included. Methodological quality and risk of bias were assessed using the Cochrane Risk of Bias tool and the PEDro scale. ResultsEight RCTs (n = 234) met the inclusion criteria. BFR training enhanced quadriceps strength and preserved or increased muscle CSA compared with low-load rehabilitation, while reducing pain and improving electromyographic activity. Outcomes were directionally consistent and comparable to HL-RT but achieved under substantially lower mechanical stress. Heterogeneity was moderate, primarily related to occlusion pressure calibration and session dosage. No serious adverse events were reported. ConclusionBFR training appears to be a safe and effective adjunct for early ACLR rehabilitation, enhancing quadriceps strength and morphology while reducing pain under low mechanical loads. Its effects are comparable to HL-RT protocols, with emerging evidence of neuromuscular benefits. Further standardization of pressure and dosage parameters is needed to refine its clinical application.